As one of semiconductor manufacturing steps, there is a step of performing a predetermined film-forming process on a surface of a substrate (a substrate to be processed having a silicon wafer and glass as a base and on which a fine pattern of electric circuit is formed). In a step of forming a gate insulating film in the predetermined film-forming process, along with a thinning of a film thickness of the gate insulating film, a change from oxide film and oxynitride film of silicon (Si) to a High-k (high dielectric constant) film is has been actively studied. As a method of forming a high-k film of ZrO2, HfO2 or the like, a sputtering method and a CVD (Chemical Vapor Deposition) method are being studied. The CVD method has a characteristic of step coverage having an advantage that exchanging of film forming sources is facilitated. Therefore, the CVD method is frequently applied in a mass production phase.
In the formation of the high-k film, MOCVD (Metal Organic Chemical Vapor Deposition) that is one kind of the CVD is applied. In the MOCVD, an organometallic source is used as a source gas. The organometallic sources are varied and each kind of them has been respectively studied. As the sources of HfO2, HfSiO4 or the like, for instance, Hf[OC(CH3)3]4 (abbreviated as Hf-OtBu), Hf[OC(CH3)2CH2OCH3]4 (hereinafter, abbreviated as Hf-MMP), Si[OC(CH3)2CH2OCH3]4 (hereinafter, abbreviated as Si-MMP), Hf [O—Si—(CH3)]4 (hereinafter, abbreviated as Hf-OSi) and so on are used. Among these, for instance, Hf-MMP and Si-MMP show a liquid phase at about 30° C. under normal pressure. Accordingly, these liquid materials are heated and transformed into gas by vapor pressure and used. The CVD using Hf-MMP, which is one of the sources of the MOCVD method is known (for example, see patent document 1).
Patent document 1: JP-A-2004-6699